Add 'ifvar' attribute to most query elements

XML 쿼리에서 'ifvar' 속성을 사용하여, 특정 변수가 있을 때만 유효한 테이블이나
컬럼, 인덱스 힌트 등을 지정할 수 있도록 합니다. 어떤 변수를 넣는지에 따라
<condition> 뿐 아니라 <table>, <column>, <index_hint? 등의 적용 여부도
XML 쿼리 수정 없이 자유롭게 컨트롤할 수 있게 됩니다.

common/framework/parsers/dbquery/columnread.php

@@ -9,6 +9,7 @@ class ColumnRead
 {
 	public $name;
 	public $alias;
+	public $ifvar;
 	public $is_expression = false;
 	public $is_wildcard = false;
 }

common/framework/parsers/dbquery/columnwrite.php

@@ -10,6 +10,7 @@ class ColumnWrite extends VariableBase
 	public $name;
 	public $operation = 'equal';
 	public $var;
+	public $ifvar;
 	public $default;
 	public $not_null;
 	public $filter;

common/framework/parsers/dbquery/condition.php

@@ -10,6 +10,7 @@ class Condition extends VariableBase
 	public $operation;
 	public $column;
 	public $var;
+	public $ifvar;
 	public $default;
 	public $not_null;
 	public $filter;

common/framework/parsers/dbquery/conditiongroup.php

@@ -9,4 +9,5 @@ class ConditionGroup
 {
 	public $conditions = array();
 	public $pipe = 'AND';
+	public $ifvar;
 }

common/framework/parsers/dbquery/groupby.php

@@ -9,4 +9,5 @@ class GroupBy
 {
 	public $columns = array();
 	public $having = array();
+	public $ifvar;
 }

common/framework/parsers/dbquery/indexhint.php

@@ -12,4 +12,5 @@ class IndexHint
 	public $index_name = '';
 	public $table_name = '';
 	public $var;
+	public $ifvar;
 }

common/framework/parsers/dbquery/query.php

@@ -131,7 +131,11 @@ class Query extends VariableBase
 			$columns = array();
 			foreach ($this->columns as $column)
 			{
-				if ($column instanceof self)
+				if ($column->ifvar && !isset($this->_args[$column->ifvar]))
+				{
+					continue;
+				}
+				elseif ($column instanceof self)
 				{
 					$has_subquery_columns = true;
 					$subquery_count_only = $count_only ? $count_only + 1 : 0;
@@ -206,7 +210,7 @@ class Query extends VariableBase
 		}
 		
 		// Compose the GROUP BY clause.
-		if ($this->groupby && count($this->groupby->columns))
+		if ($this->groupby && count($this->groupby->columns) && (!$this->groupby->ifvar || isset($this->_args[$this->groupby->ifvar])))
 		{
 			$columns = array();
 			foreach ($this->groupby->columns as $column_name)
@@ -222,7 +226,7 @@ class Query extends VariableBase
 			}
 			$result .= ' GROUP BY ' . implode(', ', $columns);
 		}
-		if ($this->groupby && count($this->groupby->having))
+		if ($this->groupby && count($this->groupby->having) && (!$this->groupby->ifvar || isset($this->_args[$this->groupby->ifvar])))
 		{
 			$having = $this->_arrangeConditions($this->groupby->having);
 			if ($having !== '')
@@ -277,6 +281,11 @@ class Query extends VariableBase
 		$columns = array();
 		foreach ($this->columns as $column)
 		{
+			if ($column->ifvar && !isset($this->_args[$column->ifvar]))
+			{
+				continue;
+			}
+			
 			$setval_string = $this->_parseCondition($column);
 			if ($setval_string !== '')
 			{
@@ -324,6 +333,11 @@ class Query extends VariableBase
 		$columns = array();
 		foreach ($this->columns as $column)
 		{
+			if ($column->ifvar && !isset($this->_args[$column->ifvar]))
+			{
+				continue;
+			}
+			
 			$setval_string = $this->_parseCondition($column);
 			if ($setval_string !== '')
 			{
@@ -407,6 +421,12 @@ class Query extends VariableBase
 		// Process each table definition.
 		foreach ($tables as $table)
 		{
+			// Skip
+			if ($table->ifvar && !isset($this->_args[$table->ifvar]))
+			{
+				continue;
+			}
+			
 			// Subquery
 			if ($table instanceof self)
 			{
@@ -465,6 +485,12 @@ class Query extends VariableBase
 		// Group each index hint by type.
 		foreach ($index_hints as $index_hint)
 		{
+			// Skip
+			if ($index_hint->ifvar && !isset($this->_args[$index_hint->ifvar]))
+			{
+				continue;
+			}
+			
 			if (!count($index_hint->target_db) || isset($index_hint->target_db['mysql']))
 			{
 				$key = $index_hint->hint_type ?: 'USE';
@@ -506,6 +532,12 @@ class Query extends VariableBase
 		// Process each condition.
 		foreach ($conditions as $condition)
 		{
+			// Skip
+			if ($condition->ifvar && !isset($this->_args[$condition->ifvar]))
+			{
+				continue;
+			}
+			
 			// Subquery
 			if ($condition instanceof self)
 			{

common/framework/parsers/dbquery/table.php

@@ -9,6 +9,7 @@ class Table
 {
 	public $name;
 	public $alias;
+	public $ifvar;
 	public $join_type;
 	public $join_conditions = array();
 }

common/framework/parsers/dbquery/variablebase.php

@@ -11,6 +11,7 @@ class VariableBase
 	 * Instance properties.
 	 */
 	public $var;
+	public $ifvar;
 	public $default;
 	
 	/**
@@ -33,7 +34,11 @@ class VariableBase
 		$params = array();
 		
 		// Process the variable or default value.
-		if ($this instanceof Query)
+		if ($this->ifvar && !isset($args[$this->ifvar]))
+		{
+			return [$where, $params];
+		}
+		elseif ($this instanceof Query)
 		{
 			$is_expression = true;
 			$value = '(' . $this->getQueryString($prefix, $args) . ')';